The most wide-spread vehicles, driven fully or partially by human power, are pedalling bicycles, pedalling three-wheels or electric bicycles respectively. This vehicle type is driven by treading pedals located on cranks which rotate a centric shaft steadily in equal sense of rotation. The centric shaft drives, by means of a chain, the shaft of a driven wheel or a driven pair of wheels in case of a tricycle. The vehicle is steered e.g. with a fork which is fastened rotatably in the bicycle frame. In this fork a front wheel is placed which is turned together with the turning fork. Due to fork turning together with the front wheel with respect to the frame with a rear wheel or a pair of rear wheels the vehicle can be steered and turned to the left or right.
In the electric bicycle or tricycle the front wheel (set of wheels) or the rear wheel (set of wheels) is driven additionally by a battery-fed electromotor. In this case the battery is located on the frame of the electric bicycle or tricycle. It is characteristic that the electric bicycle or tricycle needs riding person's cooperation. If the vehicle has to move on a plain or uphill, the riding person has to pedal as well because the electromotor only cannot drive the vehicle carrying a person.
The pedalling bicycle has many structural variants. The most important difference of individual variants consists in the location of the centric shaft, driven by cranks with pedals, and in transmitting the shaft movement to rotate the driven wheel.
The scooter is another similar vehicle. It is steered by means of a front-wheel rotatable fork too, similarly as in the pedalling bicycle or tricycle. The scooter is driven by rebounding of foot while the second riding person's foot stays on the scooter frame. The scooters can utilize the assistance of a driving electromotor as well.
The tricycle with the elliptical-principle drive is a further spread solution where the crank mechanism is rotated by a set of levers, driven by feet and hands of the riding person simultaneously. This tricycle has two lever mechanisms, one of them being controlled by right hand and right foot while the second one is controlled by left hand and left foot. Both of them move periodically which is transferred on a disk with two cranks. The cranks positions are turned by 180° mutually and the movement of the left mechanism is, with respect to the right one, shifted by half-period.
The rebounder is another human-driven vehicle. Usually, the rebounder is a single-trace double-wheel vehicle, the frame of which being modified so that a person may sit on it as on a bicycle or be hung on it. The riding person rides the vehicle in such a way that he rebounds from the ground by both feet.
Usually, the mentioned gears can be use also on training devices as pedalling devices or steppers.